[Fertility tests (hamster, electronic microscopy): are they useful?].

Tests of sperm function are often considered to be able to predict the in vivo or in vitro fertility of a given patient although they only assess part of the process of sperm fertilizing ability. It appears from the literature, that the sperm penetration assay (SPA) which investigates the sperm fusiogenic and nuclear functions cannot accurately predict the in vivo fertility and there is still much debate on the reliability of its correlation with in vitro fertilization (IVF) principally in cases of severe sperm deficiency. With the development of new techniques of assisted fertilization, by-passing the zona pellucida, a test of sperm fusion, hetero or homospecific as well, could be interesting. Considering sperm ultrastructure and beyond some specific morphological alterations of the whole sperm population that can be responsible for the infertility, such studies were not able, as yet, to reveal significative differences between semen fertile in vitro or not.